【摘要】 为开发含镁硫系易切削钢,采用高温模拟实验及热力学计算相结合的方法研究了夹杂物演变。探究了硫合金化对钢液中不同镁系夹杂物的影响及作用机理。实验结果显示,硫合金化会导致钢液中镁系夹杂物沿着MgO_（s）→2MgO·SiO_2（s）→MgO-SiO₂-MnO_（1）的路径转变。热力学计算结果表明,随着钢液中硫含量的增加,[Mg]-[S]平衡取代[Mg]-[O]平衡成为钢液中[Mg]的决定性因素。当[S]≤0.12%时,钢液中平衡[Mg]在0.00078%以上,平衡产物为固溶体MgO;当0.12%≤[S]≤0.46%时,钢液中平衡[Mg]在0.000 15%～0.000 78%,平衡产物为固溶体2MgO·SiO₂和（Mg,Mn）S;当[S]>0.46%时,钢液中平衡[Mg]在0.000 15%以下,平衡产物为液相夹杂物MgO-SiO₂-MnO和（Mg,Mn）S。更多还原

【Abstract】 In order to develop magnesium-containing resulfurized free-cutting steel,the formation and evolution of inclusions are investigated by high temperature simulation experiments and thermodynamic calculations.The effect of sulfur addition on the inclusions in liquid after magnesium treatment and mechanism are specially discussed.The experimental results show that the addition of sulfur causes the transformation of magnesium inclusions in liquid steel along the path of MgO_（s）→ 2 MgO·SiO_2（s）→ MgO-SiO₂-MnO_（1）.The results of thermodynamic calculation show that as a sufficient amount of sulfur is added to the molten steel,the [Mg] in liquid is determined by the equilibrium of [Mg]-[S] instead of [Mg]-[O].When [S]≤0.12%,the equilibrium [Mg] exceeds 0.000 78% and the equilibrium product is MgO;as 0.12% ≤[S] ≤0.46%,the equilibrium [Mg] is in the range of 0.000 15%～0.000 78% and the equilibrium product is solid solution（2 MgO·SiO₂） and（Mg,Mn）S;as [S]>0.46%,the equilibrium [Mg] is lower than 0.000 15% and the equilibrium product is liquid inclusions（MgO-SiO₂-MnO） and（Mg,Mn）S.更多还原